Views using an InOperator filter cannot be saved if one of the ValueOptions doesn't exist anymore

Going through old issues for the Bug Smash Initiative.

Now you get a fairly clear message: "No valid values found on filter: Content: Something." on the Views UI and the View stop displaying results until you fix it.

We could add a config dependency to this field, but as always, the problem then becomes, what is the correct action to take? Just stop filtering on that value? That might lead to a information disclosure. If this was the only value filtered on, it's not doing anything, should we remove it?

So, I think, what happens here is right, make the user fix the View and don't show anything until they do.

Other thoughts?

Agree with #15

Please feel free to reopen with other ideas if appropriate.